Rhodnius, Golden Oil, andMet: A History of Juvenile Hormone Research

Juvenile hormone (JH) is a unique sesquiterpenoid hormone which regulates both insect metamorphosis and insect reproduction. It also may be utilized by some insects to mediate polyphenisms and other life history events that are environmentally regulated. This article details the history of the research on this versatile hormone that began with studies by V. B. Wigglesworth on the kissing bugRhodnius prolixusin 1934, through the discovery of a natural source of JH in the abdomen of maleHyalophora cecropiamoths by C. M. Williams that allowed its isolation (golden oil) and identification, to the recent research on its receptor, termedMethoprene-tolerant(Met). Our present knowledge of cellular actions of JH in metamorphosis springs primarily from studies onRhodniusand the tobacco hornwormManduca sexta, with recent studies on the flour beetleTribolium castaneum, the silkwormBombyx mori, and the fruit flyDrosophila melanogastercontributing to the molecular understanding of these actions. Many questions still need to be resolved including the molecular basis of competence to metamorphose, differential tissue responses to JH, and the interaction of nutrition and other environmental signals regulating JH synthesis and degradation.